CAD-RADS 2.0: Comparison of methods for assessment of plaque burden

Objectives: To assess the agreement of the three methods of coronary plaque burden assessment approved by the Coronary Artery Disease-Reporting and Data System classification (CAD-RADS 2.0): coronary artery calcium (CAC) testing, segment involvement score (SIS), and visual estimate. Methods: Patients with stable chest pain who underwent coronary computed tomography angiography (CCTA) and showed signs of coronary artery disease were included in the current retrospective study. The CCTAs were independently evaluated by two board-certified radiologists. Differing results were resolved in consensus. Three separate estimates of plaque burden (P) were performed for each examination: P(CAC), P(SIS) and P(visual). Linearly weighted kappa was used to assess the agreement of the three methods. Results: The study included 132 patients (mean age 66.6 years, 68.2% male). The mean CAC score was 503.6 ± 1023.5 [SD]. CAD-RADS was 1 in 47/132 patients (35.6%), 2 in 40/132 patients (30.3%), 3 in 18/132 patients (13.6%), 4 in 24/132 cases (18.2%) and 5 in 3/132 cases (2.3%). Weighted Kappa values for method agreement were κ= 0.56 (95% CI: 0.48-0.65) for agreement between P(CAC) and P(SIS), κ= 0.67 (95% CI: 0.59-0.75) for agreement between P(CAC) and P(visual), and κ= 0.72 (95% CI: 0.64-0.80) for agreement between P(SIS) and P(visual), signifying moderate to substantial agreement. Conclusion: Results for plaque burden in CAD-RADS 2.0 are clearly influenced by the choice of assessment method. When reporting plaque burden in CAD-RADS 2.0, the method of assessment should be unequivocally named, as the three proposed methods are not interchangeable and describe different aspects of plaque burden.